text: /*-
   * Copyright (c) 1999, 2000 Robert N. M. Watson
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: src/sys/kern/kern_acl.c,v 1.2 2000/01/19 06:07:27 rwatson Exp $
   */
  
  /*
   * Generic routines to support file system ACLs, at a syntactic level
   * Semantics are the responsibility of the underlying file system
   */
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/sysproto.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/vnode.h>
  #include <sys/lock.h>
  #include <sys/namei.h>
  #include <sys/file.h>
  #include <sys/proc.h>
  #include <sys/sysent.h>
  #include <sys/errno.h>
  #include <sys/stat.h>
  #include <sys/acl.h>
  #include <vm/vm_zone.h>
  
  static MALLOC_DEFINE(M_ACL, "acl", "access control list");
  
  static int	vacl_set_acl(struct proc *p, struct vnode *vp, acl_type_t type,
  	    struct acl *aclp);
  static int	vacl_get_acl(struct proc *p, struct vnode *vp, acl_type_t type,
  	    struct acl *aclp);
  static int	vacl_aclcheck(struct proc *p, struct vnode *vp, acl_type_t type,
  	    struct acl *aclp);
  
  /*
   * These calls wrap the real vnode operations, and are called by the 
   * syscall code once the syscall has converted the path or file
   * descriptor to a vnode (unlocked).  The aclp pointer is assumed
   * still to point to userland, so this should not be consumed within
   * the kernel except by syscall code.  Other code should directly
   * invoke VOP_{SET,GET}ACL.
   */
  
  /*
   * Given a vnode, set its ACL.
   */
  static int
  vacl_set_acl(struct proc *p, struct vnode *vp, acl_type_t type,
      struct acl *aclp)
  {
  	struct acl inkernacl;
  	int error;
  
  	error = copyin(aclp, &inkernacl, sizeof(struct acl));
  	if (error)
  		return(error);
  	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
  	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
  	error = VOP_SETACL(vp, type, &inkernacl, p->p_ucred, p);
  	VOP_UNLOCK(vp, 0, p);
  	return(error);
  }
  
  /*
   * Given a vnode, get its ACL.
   */
  static int
  vacl_get_acl(struct proc *p, struct vnode *vp, acl_type_t type,
      struct acl *aclp)
  {
  	struct acl inkernelacl;
  	int error;
  
  	error = VOP_GETACL(vp, type, &inkernelacl, p->p_ucred, p);
  	if (error == 0)
  		error = copyout(&inkernelacl, aclp, sizeof(struct acl));
  	return (error);
  }
  
  /*
   * Given a vnode, delete its ACL.
   */
  static int
  vacl_delete(struct proc *p, struct vnode *vp, acl_type_t type)
  {
  	int error;
  
  	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
  	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
  	error = VOP_SETACL(vp, ACL_TYPE_DEFAULT, 0, p->p_ucred, p);
  	VOP_UNLOCK(vp, 0, p);
  	return (error);
  }
  
  /*
   * Given a vnode, check whether an ACL is appropriate for it
   */
  static int
  vacl_aclcheck(struct proc *p, struct vnode *vp, acl_type_t type,
      struct acl *aclp)
  {
  	struct acl inkernelacl;
  	int error;
  
  	error = copyin(aclp, &inkernelacl, sizeof(struct acl));
  	if (error)
  		return(error);
  	error = VOP_ACLCHECK(vp, type, &inkernelacl, p->p_ucred, p);
  	return (error);
  }
  
  /*
   * syscalls -- convert the path/fd to a vnode, and call vacl_whatever.
   * Don't need to lock, as the vacl_ code will get/release any locks
   * required.
   */
  
  /*
   * Given a file path, get an ACL for it
   */
  int
  __acl_get_file(struct proc *p, struct __acl_get_file_args *uap)
  {
  	struct nameidata nd;
  	int error;
  
  	/* what flags are required here -- possible not LOCKLEAF? */
  	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
  	error = namei(&nd);
  	if (error)
  		return(error);
  	error = vacl_get_acl(p, nd.ni_vp, SCARG(uap, type), SCARG(uap, aclp));
  	NDFREE(&nd, 0);
  	return (error);
  }
  
  /*
   * Given a file path, set an ACL for it
   */
  int
  __acl_set_file(struct proc *p, struct __acl_set_file_args *uap)
  {
  	struct nameidata nd;
  	int error;
  
  	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
  	error = namei(&nd);
  	if (error)
  		return(error);
  	error = vacl_set_acl(p, nd.ni_vp, SCARG(uap, type), SCARG(uap, aclp));
  	NDFREE(&nd, 0);
  	return (error);
  }
  
  /*
   * Given a file descriptor, get an ACL for it
   */
  int
  __acl_get_fd(struct proc *p, struct __acl_get_fd_args *uap)
  {
  	struct file *fp;
  	int error;
  
  	error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
  	if (error)
  		return(error);
  	return vacl_get_acl(p, (struct vnode *)fp->f_data, SCARG(uap, type),
  	    SCARG(uap, aclp));
  }
  
  /*
   * Given a file descriptor, set an ACL for it
   */
  int
  __acl_set_fd(struct proc *p, struct __acl_set_fd_args *uap)
  {
  	struct file *fp;
  	int error;
  
  	error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
  	if (error)
  		return(error);
  	return vacl_set_acl(p, (struct vnode *)fp->f_data, SCARG(uap, type),
  	    SCARG(uap, aclp));
  }
  
  /*
   * Given a file path, delete an ACL from it.
   */
  int
  __acl_delete_file(struct proc *p, struct __acl_delete_file_args *uap)
  {
  	struct nameidata nd;
  	int error;
  
  	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
  	error = namei(&nd);
  	if (error)
  		return(error);
  	error = vacl_delete(p, nd.ni_vp, SCARG(uap, type));
  	NDFREE(&nd, 0);
  	return (error);
  }
  
  /*
   * Given a file path, delete an ACL from it.
   */
  int
  __acl_delete_fd(struct proc *p, struct __acl_delete_fd_args *uap)
  {
  	struct file *fp;
  	int error;
  
  	error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
  	if (error)
  		return(error);
  	error = vacl_delete(p, (struct vnode *)fp->f_data, SCARG(uap, type));
  	return (error);
  }
  
  /*
   * Given a file path, check an ACL for it
   */
  int
  __acl_aclcheck_file(struct proc *p, struct __acl_aclcheck_file_args *uap)
  {
  	struct nameidata	nd;
  	int	error;
  
  	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
  	error = namei(&nd);
  	if (error)
  		return(error);
  	error = vacl_aclcheck(p, nd.ni_vp, SCARG(uap, type), SCARG(uap, aclp));
  	NDFREE(&nd, 0);
  	return (error);
  }
  
  /*
   * Given a file descriptor, check an ACL for it
   */
  int
  __acl_aclcheck_fd(struct proc *p, struct __acl_aclcheck_fd_args *uap)
  {
  	struct file *fp;
  	int error;
  
  	error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
  	if (error)
  		return(error);
  	return vacl_aclcheck(p, (struct vnode *)fp->f_data, SCARG(uap, type),
  	    SCARG(uap, aclp));
  }
  